Iliacus
Musculus iliacus
A fan-shaped muscle filling the iliac fossa. It joins the psoas tendon to insert on the lesser trochanter and is supplied by the femoral nerve.
Overview
Iliacus arises from the upper two-thirds of the iliac fossa, the inner lip of the iliac crest, the ala of the sacrum and the anterior sacroiliac ligaments. Its fibres converge and fuse with the lateral side of the psoas tendon, with some fibres inserting on the shaft just below the lesser trochanter. It flexes the hip with psoas and is particularly active in holding the pelvis upright during standing and walking. It is supplied by the femoral nerve, which runs in the groove between iliacus and psoas. The caecum (right side) and sigmoid colon (left side) lie on it.
Anatomy
- Origin
Iliac fossa, iliac crest, ala of the sacrum and the anterior sacroiliac ligaments.
- Insertion
Lesser trochanter of the femur (via the psoas tendon) and the shaft below it.
- Action
Flexion of the hip; flexion of the trunk on the thigh.
- Innervation
Femoral nerve.
- Nerve roots
L2–L3
- Arterial supply
Iliac branch of the iliolumbar artery; deep circumflex iliac artery; obturator artery.
Function
- Flexes the hip (with psoas)
- Stabilises the pelvis on the femur
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.